Beta-(2-benzothienyl)-alpha-amino propionic acid and salts



Patented Aug. 8, 1950 "UNITED STATES PATENT 'O FFI-CE --BETA-,(2BENZOTHIENYL)--ALPHA-AMINO 'BROPIONICj ACID AND SALTS Souren Avakiangfilreland, and Gu'stavl Martin,

. :Philadelphia,fiPa., assignors' to The National 'Drugycompany, Philadelphia, 1 Pa., a: corporationof Bennsylvania -No Drawing. Application Marches-19 18,

Serial No. 17,115 I 2 Claims. (01. 260-329) Our inventiomrelatesto new chemotherapeutic ;process -'m ay?be illustrated;v graphically =by.the" fol-'- agents:- More-p articularly, it concerns the, novel lowing chemical equations: compound 'beta-t2 benzothienyl)-alpha amino- I 60,062.];

propionic acid and its salts, as wellas a method for-preparing= the same. Our novel compound 5 H- H0 possesses the following structural formula? I OOGIHS v I sodium alcoholate om-cm-ooon NH, 000cm,

1 CH: NHCHO We have found that this amino acid and its salts \S possess outstanding anti-bacterial properties.

They are highly effective displacing agents for the naturally occurring tryptophane which is one of the amino acids essential for bacterial growth.

then neutralize with Our new amino acid possesses a structure simi- O lar to that of tryptophane, wherein a benzothienyl radical is substituted for the indyl radical. Owing to this relationship a very lowconcentration s of our new chemotherapeutic agents will efiec- The preparation of our new compounds W111 be tlvely mhlblt bacterial growth partlcul-afly of better understood upon consideration of the folpathogenic bacteria.

lowing specific example. Obviously our invenour new chemotherapeuuc agents maybe taken tion is not limited to the specific auxiliary reorauy mJected mtravenously or Incorporated in actants and reaction conditions set forth in this an ointment or powder and applied externally. A convenient form for topical application is an g ggi g' i z gig g g g g g g i g ointment containing about 5% of the novel amino acid. The salts may conveniently be formed from Example theamino acid by the addition of appropriate acids, particularly mineral acids such as hydro- T0 So n of grams of Sodium in 100 cc.

chloric acid. In turn such salts are converted of absolute EJ001101 there w added grams back to the amino acid by neutralizatiomprefof diethyl formylaminomalonate followed by 9.2

- erably with ammonium hydroxide. The amino grams of -c orom y be p e acid is sparingly soluble in aqueous ethyl alcohol, mixture was then heated to reflux for a period of whereas its salts are readily soluble therein. The 3 hours. he p n it s p d o ice Water, amino acid is a white crystalline substance having and a p c p e recovered y filtration In t s a melting point of 279-280 C. 4 manner there was obtained 29 grams of a crude Our new chemotherapeutic agents may be product melting at 103-105 C. A sample of this prepared by first condensing 2-chloromethylproduct, recrystallized from petroleum ether, benzothiophene with diethyl formylaminomalomelted at 106-107 C. This intermediate is the nate to form ethyl alpha-carbethoxy-alphaethyl alpha oarbethoxy alpha formylamidoformylamido beta (2 benzothienyl) propiobeta-(Z-benzothienyl) -propionate. nate, and then heating said intermediate with a 14 grams of the crude intermediate obtained as concentrated mineral acid to produce the corredescribed above was heated to reflux with 200 cc.

spending salt of our novel amino acid. The latter of concentrated hydrochloric acid over a period can then be obtained by neutralizingthe salt of 6 hours. The resultant solution was then with an alkali suchas ammonium hydroxide. The evaporated to dryness under reduced pressure,

and the residue obtained was dissolved in 75 cc. of 50% ethyl alcohol. Said solution was thereupon neutralized by the addition of ammonium hydroxide forming a precipitate consisting of 6.5 grams of the desired beta-(2-benzothienyl)- alpha-aminopropionic acid. This precipitate was washed with 50% ethyl alcohol and dried to give a crystalline product having a melting point of 279-280 C. A sulfur analysis of this product showed 14.08% of sulfur as against a theoretical content of 14.48%.

The 2-chloromethyl-benzothiophene employed as an initial material in the preparation of our new chemotherapeutic agents, is itself a novel compound. We have prepared it by reacting benzothiophene with formaldehyde and hydrogen chloride. The position of the chloromethyl thus introduced has been determined by reacting the resultant product with potassium cyanide and then saponifying the nitrile group so substituted for the chlorine of the chloromethyl group.

The product thus obtained had the same me1t-. 1'

ing point as the benzothiophene-2-acetic acid prepared from 2-bromo.-benzothiophene according to the method disclosed by Crook and Davis in Journal of the Chemical Society, 1937, page 1697.

Specifically, we prepared the 2-chloromethylbenzothiophene employed in the foregoing example as follows: I I 1 A rapid current of hydrogen chloride was passed through a. vigorously stirred mixture of 20.1 grams (0.15 mole) of benzothiophene and 20 cc. of 40% formaldehyde, cooled in an ice bath. The reaction temperature Was kept at 20-25 C. for 5 minutes and was then reduced to 10-15 C. After half an hour, the reaction mixture was diluted with ice water and extracted with ether. The ether layer was washed with an aqueous sodium bicarbonate solution, and then dried over sodium sulfate. Distillation of the ether extract gave 15.5 grams. (56.3% yielcD'ofv a product boiling at 129-131 C. under a reduced pressure of 5.0 mm. Hg. Crystallization of this product from petroleum ether resulted in a, white crystalline material that melted at 4445 C. This was the 2-chloromethyl-benzothiophene whose identity was established as indicated above.

We claim:

1. A compound selected from the group consisting of beta-(2 -benzothienyl) alpha amino propionic acid and its salts.

I 2. Beta-(Z-benzothienyl)-alpha-amino propionic acid.

SOUREN AVAKIAN. GUSTAV J. MARTIN.

-' REFERENCESCITED The following references are of record in the file {01" this I. patent:

Albertson, J. chem. Soc, 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF BETA-(2 BENZOTHIENYL) - ALPHA - AMINO PROPIONIC ACID AND ITS SALTS. 